The present invention relates to a motor-vehicle seat unit and, more particularly, to a seat unit which has a seat and two rail pairs for the longitudinal adjustment of the seat. Each rail pair is made up of a seat rail and a floor rail, and fixing regions which extend downwards such that they face away from one another and have a hole for a fixing screw to effect a screwed connection of the seat unit to the body platform of the motor vehicle at the end regions of the floor rails.
A known seat unit is shown in UK Patent Specification No. 2,113,538. It describes a seat unit with two rail pairs of different design. At both ends, the floor rail of each rail pair has in each case a fixing region in which the hole for the screw-fastening of the respective rail end is provided. The fixing region is situated on an additional part which is produced separately from the floor rail and is connected to the latter in a suitable manner, for example by welding. For the rear region of a floor rail, the fixing region extends virtually at right angles to the direction of displacement, whereas, for the front ends of the floor rails, the fixing regions are different, namely, on one hand extending obliquely forwards and downwards at an angle of about 45 degrees and, on the other hand, extending in a manner offset in parallel to the plane of the displacement of the seat.
The fixing regions make automatic screwing in of the seat unit possible, at least in part. Completely automatic installation is, however, not achieved with the solutions already known. Furthermore, these known solutions have the decisive disadvantage that the floor rails are not connected directly to the body platform of the motor vehicle but with the interposition of the additional parts which project outwards at the ends of the respective floor rail and have a lower rigidity than the floor rail itself. The quality of the fixing of the floor rail to the body platform of the motor vehicle then depends decisively on the design of the respective additional parts and, in particular, on their connection to the floor rail. In the case of the known seat unit, an advantageous mutual reinforcement of the floor rail and of the immediately adjacent subregion of the body platform is not achieved. Problems with respect to tear-out strength also arise in the case of seat belts which are fixed to the seat.
The foregoing is the starting point of the present invention which has an object of improving the seat unit such that, on one hand, it can be screwed automatically to the body platform at all four fixing points without the need to alter the seat setting during screwing and, on the other hand, has a sufficiently rigid connection, in particular a sufficiently firm connection for seat belts which are fixed to the seat, to the body platform.
This object has been achieved, starting from the known seat unit, by the fact that the fixing regions (a) are provided in the floor rail itself, in particular in each case at a distance from the free ends of the latter and in a profile region, extending essentially parallel to the body platform, of the floor rail, (b) are joined directly to a steep wall and, with the latter, in each case form a ramp, and (c) are oriented such that they enclose as small an angle as possible with the floor rail, although this angle is sufficiently large that, in an installation setting of the seat unit, the axes of the holes extend in front of the front side of the seat and behind the rear side of the seat with a clearance of a few centimeters, which makes possible the use of a screwdriver unit.
The seat unit of the present invention thus achieves a very firm connection of the floor rails to the body platform. The high rigidity of floor rails of tear-out-resistant longitudinal guides, which is essentially achieved by vertical profile regions extending essentially at right angles to the body platform, is brought into the fixing region and is not lost, as was the case in the prior art, due to the additional parts. Furthermore, the fixing regions do not extend the total length of the floor-rail units. On the contrary, the floor rail retains the length which is required for sufficient engagement with the seat rail over the entire displacement path.
The present invention makes possible completely automatic installation of the seat in all four fixing points at the end regions of the floor rail. The installation time for a seat unit is thereby markedly reduced. This reduction is not at the expense of the quality of the connection between floor rail and body platform. The quality of connection achieved is indeed the same as that in the case of currently predominant techniques for fixing floor rails on the body platform, namely screwing the floor rail directly to the body platform.
In a side view, i.e. transversely to the direction of displacement, the fixing region of the present invention, together with the steep wall, has the form of a sawtooth projecting upwards or downwards from the profile region of the floor rail. The fixing region extends essentially parallel to the body platform. The hole is as near as possible to the transition between the undisturbed bottom profile region and the fixing region. The fixing region itself is configured to be as short as possible, as seen in the direction of displacement, and its length is determined essentially by the head diameter of the fixing screw utilized. The steep wall is likewise as short as possible, preferably extending parallel to the direction of the axis of the hole. It is preferably shorter than the fixing region, again as seen in the displacement direction.
In the fixing regions, the body platform is of corresponding configuration, i.e. has comparable slopes preferably provided in crossmembers or supports which project upwards from the floor panel. By virtue of the oblique position at the front and at the rear of the body platform components or fixing regions, the seat unit is aligned and centered during installation. During their installation on the floor panel of the body platform, which is generally effected by spot-welding, the crossmembers or supports of the body platform, in which there are internal threads aligned with the holes of the fixing regions, are guided by a template in order to make possible precise association with the floor rails. The internal threads are formed by weld nuts, insert nuts or the like.
In an advantageous further embodiment, the fixing regions are formed in a cup-shaped part which, as seen from the hole in the fixing region, is connected all the way around to the bottom profile region of the floor rail, either integrally or by a suitable connection, e.g. welding. With the cup-shaped design, the fixing region is stiffened even further and is better connected to the bottom profile region of the floor rail. In this way, the rigidity of the floor rail is even more favorably exploited in the connection region and imparted to the body platform.
The fixing region is part of the bottom profile of the floor rail and/or part of a separate insert. In a currently preferred embodiment, a recess is provided in the floor rail and extends essentially in a U-shaped form, leaving a tab which is bent downwards or upwards, and forms part of the fixing region. In addition, an insert is provided, likewise forming a fixing region, but also forms the steep wall and is connected to the bottom profile of the floor rail at least in front of and to the rear of the hole as seen in the displacement direction. This insert is preferably cup-shaped.
The rails can be manufactured from steel, aluminum or some other suitable material. Rail profiles which are highly suitable for carrying out the invention are shown, for example, in German Patent No. 3,143,431 and German Offenlegungsschrift No. 2,545,763. In these longitudinal guides, the respective floor rail has a bottom profile region which permits the formation of the fixing region according to the present invention.